The concept of the graviton as a quantum particle is a hypothetical idea that arises when attempting to reconcile quantum mechanics with the theory of gravity. Quantum mechanics successfully describes the behavior of particles at the microscopic level, while the theory of gravity, general relativity, explains the gravitational interactions between massive objects on a macroscopic scale.
In the framework of quantum field theory, which combines quantum mechanics and special relativity, the other fundamental forces (electromagnetism, weak nuclear force, and strong nuclear force) are described by the exchange of particles known as gauge bosons. For example, photons mediate the electromagnetic force. In a similar vein, if gravity were to be described in the same way, it would require the existence of a hypothetical particle called the graviton.
However, it is important to note that the theory of quantum gravity, which unifies quantum mechanics and general relativity, is still an active area of research, and a consistent quantum theory of gravity, including the existence of gravitons, has not yet been established. The nature of gravity at the quantum level remains a subject of ongoing investigation and theoretical exploration.
It's worth mentioning that the quantization of gravity and the existence of gravitons are currently speculative and theoretical concepts. The actual experimental detection of gravitons or confirmation of their existence has not been achieved to date. Resolving the nature of gravity at the quantum level is one of the key challenges in theoretical physics and a topic of ongoing research.